I have a new Viking Sapphire and while I love my machine, I would trade you any day! They just don't make the machines like they used to so I say use yours 'til it dies!! :)
I had that exact same machine! My husband bought it for me for my birthday in July of 1980. We had been married for 1 year at the time. I 'retired' it in 2000 when I bought my Viking.